From: Stephen Hemminger <[EMAIL PROTECTED]> Date: Mon, 8 Oct 2007 14:03:01 -0700
> On Mon, 08 Oct 2007 14:40:22 -0700 > "Michael Chan" <[EMAIL PROTECTED]> wrote: > > > On Mon, 2007-10-08 at 12:08 -0700, Stephen Hemminger wrote: > > > On Mon, 08 Oct 2007 20:34:41 +0200 > > > "Eliezer" <[EMAIL PROTECTED]> wrote: > > > > > > > > * The MACRO's for 64 bit stats look like they could be done with > > > > > u64 and/or turned into inline's. > > > > > > > > The MACRO's modify some of their arguments, plus they need to work on 32 > > > > bit machines (are 64 bit counters always available on 32 bit machines?). > > > > so using an inline would allow the inline to be more readable but > > > > calling it would get ugly. > > > > I'm open to suggestions. > > > > > > > > > > u64 exists on all platforms (including 32 bit). > > > > > > > I think the biggest problem with these 64-bits counters (and 64-bit > > addresses) is that the hardware treats them as big endian and they get > > DMA'ed in big endian format. We control the byte swap so that 32-bit > > quantities will have the correct endianness, but the high and low 32-bit > > words will be in the wrong spots on little endian machines. That's why > > we need to separate the high and the low words and convert them back and > > forth. > > > There are types and tools for checking endianness see be64, etc. It's not a be64 Stephen, Michael is trying to explain this. They configure the hardware to swap the bytes within a 32-bit word into cpu endianness, but the chip doesn't swap the 32-bit words within a 64-bit word properly, which is why the macros are necessary. - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
